Magnetic material and method of producing same

ABSTRACT

A pilferage prevention system is disclosed in which articles to be protected are provided with plural magnetic fields in different directions, each of which is detected such that neutralization of the plural fields for the purpose of preventing detection is precluded.

United States Patent Trikilis 1*Dec. 25, 1973 MAGNETIC MATERIAL ANDMETHOD OF [56] References Cited PRODUCING SAME UNITED STATES PATENTS[76] Inventor; Emmanuel M, Trikilis, 170 2,774,060 12/1956 Thompson324/34 0 Maplewood Ave Columbus, Ohio 2,812,203 11 1957 Scholten 335 30243213 2,827,437 3/1958 Rathenau.... 335/284 X 3,177,546 4/1965 Bey335/302 X Notice: The portion of the term of this 3,191,106 6/1965Baermann 335/303 X patent subsequent to Dec 13, 1983, 3,423,674 1/1969Goldsmith et a1. 324/45 has been disclaimed. [22] Filed: 1972 PrimaryExaminer-Alfred E. Smith [21] Appl. No.: 215,385 AttorneyDean S. Edmondset a1.

Related US. Application Data 7 A Q 7 [60] Continuation of Ser. No. 733,163, May 29, 1968, 57 S R K233 2 152; 1:: 3 2 g 2 531253 A pilferageprevention system is disclosed in which articles to be protected areprovided with plural magnetic fields in different directions, each ofwhich is de- 26 tected such that neutralization of the plural fields for[58] mid orgs'rziiiif"iiiiiii'ffiiiiaa/u 41 45- the purpose ofpreventing is precluded.

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ATTORNEYS MAGNETIC MATERIAL AND METHOD OF PRODUCING SAME REFERENCES TORELATED APPLICATIONS Various radioactive and electronic systems havebeen designed to protect articles from unauthorized removal. However,each has attendant disadvantages. The radioactive systems presentproblems in handling and the electronic systems are costly to installand maintain. In my copending application, Ser. No. 412,893, for SYSTEMAND METHOD FOR PRE- VENTING PILFERAGE BY DETECTION OF MAG- NETIC FIELDS,filed Nov. 23, 1964, a system was described in which articles such asgoods or commodities, easily accessible to the public, are protected bybeing given a detectable magnetic field which must be demagnetized byauthorized personnel before it may be removed from a security area. Amagnetic sensing device is placed at the exit or doorway to detect anyarticles which have not been exposed to the demagnetizer. The securityarea includes or terminates in a pathway, which is defined to mean anyarea, route or line of travel where the system is established to detectpilfer ers. Various possible routes may exist through such pathway, eachsuch route constituting a way in which a person might pass through thepathway. For example, one such route may include picking up a protectedarticle within the security area or pathway and exiting therefromwithout having such goods demagnetized. In another such route, theprotected goods picked up may be demagnetized prior to leaving. A morecomplete explanation of the pilferage system is contained in US. Pat.No. 3,292,080.

FIG. 7 illustrates goods 1 which are to be protected from theft bygiving them a detectable magnetic field. A pathway 3 is privided withinwhich the system is arranged. It is contemplated that pathway be usedherein to mean any area, route or line of travel where the systemisestablished to detect pilferers. This pathway may be situated in alibrary, department store, plant or anywhere else where goods are to beprotected.

A demagnetizer 2 is provided in a portion of pathway 3,. Thedemagnetizer 2 is usually situated at a check-out counter 8 or the likenear the exit of the pathway. One type of demagnetizer that may be usedis a common current carrying coil which, when energized, produces amagnetic field within the coil.

A magnetic sensing device 4 is positioned at the exit of the pathway.This magnetic sensing device 4 is designed to detect the magnetic fieldof any goods I which are to be protected and have not been demagnitized.It is preset to sense only magnetic fields having predetermined valuesof B and H In this manner, foreign items which display a magnetic fielddifferent than these pre-determined values will not detected (sic) whenpassing by the magnetic sensing device 4.

The sensing device 4 may be selected from any wellknown instruments,such as a magnetomer, gradiometer, fluxmeter, gaussmeter andpermeameter. These instruments are usually protected from disturbancesby outside magnetic fields by means of high permeable shielding.

An alarm 5 will be actuated by the magnetic sensing device 4 when amagnetic field, emanating from the protected goods is detected. Thealarm may be a visible or an audible warning device. The magneticsensing device 4 could also be used to actuate and lock a door or aturnstile, positioned at the exit to the pathway, and thus prevent thethief from leaving the security area.

There are two possible routes the goods 1 may follow through the system.If the goods follow the normal and proper channel (line 7 of FIG. 7)they are taken to a check-out counter 8 where the goods are deactivatedby the demagnetizer 2. The demagnetized goods are then exposed to themagnetic sensing device 4. The sensing device 4 will not, however,actuate the alarm 5 since no magnetic field will be present to bedetected. Thus, the goods will be permitted to leave the security area.The alternate route that the goods 1 may follow is illustrated by line 6of FIG. 7. The goods 1 are carried directly through the pathway withoutpassing in contact with the demagnetizer 2. When the goods I reach themagnetic sensing device 4, the magnetic field of the goods will bedetected. The magnetic sensing device 4 will in turn actuate alarm 5 andthe pilferer will be exposed.

The system operates satisfactorily with any article having a detectablemagnetic field. Therefore, the article need only have a singledetectable magnetic field to operate satisfactorily with the pilferageprevention system described above.

However, one disadvantage of using only a single detectable magneticfield is that the system may be defeated by neutralizing the singlemagnetic field of the protected article by an external magnetic source.This may be accomplished by placing another device of the same magneticstrength having an opposed polarity immediately adjacent to theprotected and magnetized article. One magnetic field then acts toneutralize the other in the same manner as that occurs when two barmagnets are placed side by side with poles directly opposite. Thus, itcan be seen that if such were to occur, the removal of the articles byan unauthorized person in the aforementioned system would not bedetected.

The present invention relates to magnetized articles suitable for use inpilferage prevention systems and to a method of magnetizing the articlesto be used in said systems.

The magnetized articles are not limited to any particular shape and maybe rectangular, circular or have any three dimensional configuration, aslong as they are capable of retaining a detectable magnetic field. Themagnetized articles may be the goods to be protected themselves wherethey are capable of retaining a detectable magnetic field or they maytake a form so as to be readily attachable to the goods or products tobe protected.

One feature of the present invention is that the articles to beprotected are capable of retaining a plurality of magnetic fields so asnot to be subject to neutralization by an external magnetic source. Thisis accomplished by individually magnetizing these articles themselves toprovide at least two separate detectable fields where they are in theform of goods or commodities, or by attaching to the goods an article inthe form of a magnetic flat component having at least two separatemagnetic fields. Whether the articles are in the form of magnetizedcommodities or are in the form of the flat magnetized components, nomatter what type of external neutralizing sources are used, only one ofthe two magnetic fields will be neutralized since each article has twooppositely disposed magnetic fields.

A further feature of this invention is the method of magnetizing thearticles. The article may be magnetized individually so a plurality ofnorth-south magnetic fields may be produced as described above, or thearticles may be magnetized in bulk, wherein only a single magnetic fieldis applied to the individual article.

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily appreciated as the same becomesbetter understood by reference to the following detailed descriptionwhen considered in connection with the accompanying drawings wherein:

FIG. 1a illustrates one embodiment of a magnetizer used in theinvention;

FIGS. lb and 1c illustrate two rectangular magnetized components havinga magnetic field produced by the magnetizer of FIG. la;

FIG. 2a illustrates a second embodiment of a magnetizer used in theinvention;

FIG. 2b illustrates a magnetized article made with the magnetizer ofFIG. 2a;

FIG. 3a shows a third embodiment of a magnetizer used in the invention;

FIGS. 3b and 3c show magnetized articles made with the magnetizer ofFIG. 3a;

FIGS. 4a and 4b illustrate two additional types of magnetizers;

FIGS. 40 and 4d illustrate the magnetized articles made with the type ofmagnetizers of FIGS. 4a and 4b;

FIG. 5a is a commodity protected with an article of the presentinvention;

FIGS. 5b and 50 show magnetized commodities;

FIG. 6 shows apparatus used in the method of magnetizing materials inbulk; I 1

FIG. 7 is a schematicillustration of a pilferage prevention system asshown in U. S. Pat. No. 3,292,080.

Various embodiments of the magnetized article to be used are shown inthe drawings. There is no limitation on the size or shape of thearticle, and it need only have the property of residual magneticinduction, that is, it must be capable of retaining a detectablemagnetic field. An example of such material is one with ferromagneticproperties. As indicated in my copending application, Ser. No. 412,893,for SYSTEM AND METHOD FOR PREVENTING PILFERAGE BY DE- TECTION OFMAGNETIC FIELDS, filed Nov. 23, 1964, the magnetized article may be theprotected goods themselves where they are capable of retaining amagnetic field, for example, an iron hammer or screwdriver, or thearticle may take the form of a flat component that is physicallyattached to the goods to be protected such as a flat metallic strip asshown in FIGS. 5a, 5b and 50. To facilitate the description, thearticles shown in the drawings are flat strip and circular components ofthe type that could be easily attached to goods or commodities to beprotected.

FIG. 1a discloses a double-headed magnetizer 1 designed to produce themagnetic articles of the present invention. The double-headed magnetizer1 is provided with a base 2 whereon two conventional C-shaped yokes 3and 4 are mounted in a longitudinal arrangement, the open ends facingupwardly. Around the base of each yoke 3 and 4 is wound a coil 5 and 6designed to carry the magnetic current. The coils 5 and 6 are wound insuch a manner that magnetic fields of oppo site polarity are producedwhen current is passed through them. In this embodiment the south polesare shown adjacent each other while their respective north poles are onthe opposite end of the magnetizer unit 1.

It will be understood by those skilled in the art that an articlecapable of retaining a residual magnetic induction may be magnetized byplacing it directly over the open ends of the yoke pieces 3 and 4 andenergizing the coils 5 and 6. The energized coils 5 and 6 producemagnetic flux fields between the two north and south poles which act toreorient the molecular structure of the magnetizable article. Thearticle, such as the fiat strip component 7 shown in FIG. 1b, isprovided with a pair of north-south magnetic fields, with the two southpoles at its respective center and north poles at its ends. Anon-magnetic material may be placed at the center of the article 7between the two magnetic fields in any convenient manner to act as ameans for definitely separating the two fields.

Alternately, a strip component 8 may be formed by two pieces ofmagnetized material 9 and 10 set in a non-magnetic material 11 such asplastic or cardboard to form a composite structure. This strip component8 may be formed by first separately magnetizing the individual pieces ofmaterial and then setting them in the plastic or cardboard, or bysetting the individual pieces in the plastic or cardboard and utilizingthe magnetizer 1 as above.

With this arrangement of double magnetic fields in the component, theproblem of neutralizing the magnetized component is almost totallyeliminated, since a neutralizing magnet having one magnetic field cannotbe placed over both the magnetic fields of the article and one or theother will remain detectable.

FIG. 2a shows a double-headed magnetizer 12 similar to the magnetizer 1,except the coils l3 and 14 wound around the yokes l5 and 16 produce anopposite polarity to the magnetizer 1. In this way, the north poles areadjacent to each other while the south poles are on the opposite end ofthe magnetizer unit 12. The strip component 17 shown in FIG. 2b formedby this doubleheaded magnetizer 12 thus has a polarity opposite to thestrip component 7 of the first embodiment.

A non-magnetic material may also be placed between the two magneticfields. Also, a strip component may be formed by two pieces ofmagnetized material set in non-magnetic material, to form a compositestructure in the same manner as component 8 of the first embodiment.

FIG. 3a shows a third type of double-headed magnetizer 18 wherein twoC-shaped yokes 19 and 20 are placed on a base 21 facing upwardly in aparallel, sideby-side relationship rather than in a longitudinal line asillustrated in FIG. 1a and FIG. 2a. The coils 22 and 23 are wound aroundthe bases of their respective yokes 19 and 20 in such a way so as toproduce magnetic fields of opposite polarity when the current is passedthrough the coils. That is, one yoke of the magnetizer 18 has anorth-south polarity while the other yoke immediately adjacent theretohas a south-north polarity.

FIG. 3b illustrates a magnetized strip component 24 produced by themagnetizer 18. In this figure the two detectable magnetic fields arearranged in parallel, side-by-side relationship to form the doublepolarity magnetized strip component 24.

As in the first two embodiments, the strip component 24 may be providedwith a strip of non-magnetic material between the two fields.Alternately, a strip component article 25 may be formed using two piecesof magnetized material 26 and 27 of opposite setting on a nonmagneticbase 28.

A variety of magnetizers and components are contemplated by thisinventiomthe only limitation being that the magnetizer carry at leasttwo magnetic yokes of opposite polarity to provide the component withtwo magnetic fields in order that both fields will not be subject toneutralization from an external magnetic source.

FIG. 4a shows a cross-shaped magnetizer 30 capable of producing fourmagnetic fields. The coils 31 are so wound on the yoke section 32 so asto produce a south polarity at the center of the magnetizer 30 and northpolarities at the end of the magnetizer yokes. Thus, by placing anyarticle to be magnetized above or in juxtaposition with the magnetizer30, it will receive four magnetic fields extending radially outwardlyfrom the center of the magnetizer.

This type magnetizer 30 is particularly convenient for use in producingcircular magnetized components 33 and 34 as shown in FIGS. 4c and 4d.The same principle applies to the circular components 33 and 34 as tothe longitudinal strip components described above. The opposite polarityarrangement of the detectable magnetic fields precludes neutralizationby an external magnetic source. To facilitate handling, a circularcomponent 34 may be provided with a hole 35 in its center.

It is understood that this type magnetizer may have its coils wound insuch a manner so the current flows in the opposite direction in orderthat the center of the magnetizer forms a north pole and the oppositeends form south poles. This type of magnetizer 36 is shown in FIG. 4b.The operation is the same as the described above, with merely a changein polarity. The article to be detected is given a plurality of radiallyspaced magnetic fields which are not subject to neutralization from anexternal source.

As indicated above the article to be magnetized is not limited to anyparticular size or configurationFlG. 5a illustrates a magnetizedcomponent type article 40 which is shown attached to the goods orcommodity 41 such as a library book or the like. It is understood thisattachment may be made in any convenient manner such as by using glue orpressure-sensitive tape. Also, any goods or commodities which are to beprotected, and are capable of retaining a detectable magnetic field, maybe directly magnetized with a plurality of magnetic fields. For example,metallic tools or appliances could be given a plurality of detectablemagnetic fields. FIG. 5b illustrates a screwdriver 42 and FIG. 5cillustrates a hammer 43 both of which have been magnetized according tothis invention. Such goods could be magnetized by a longitudinalmagnetizer 1, 12 or 18.

Differently shaped commodities, such as a frying pan, I

not shown, could be magnetized by a cross-shaped magnetizer 30 or 36.The type of magnetizer used depends upon which is the more convenient touse.

Where an article to be protected is made in great quantity, it may notbe economically feasible to individually magnetize each article in orderto provide it with a plurality of magnetic fields.

The detection system of my copending application, Ser. No. 412,893, forSYSTEM AND METHOD FOR PREVENTING PILFERAGE BY DETECTION OF MAGNETICFIELDS, filed Nov. 23, 1964, operates in the same manner whether thearticles or goods to be protected have a single or a plurality ofmagnetic fields. Thus, it may be economically preferable to magnetizethe articles in bulk thereby giving them only a single detectable field.In order that the pilferage prevention system operates more efficiently,the articles or goods to be protected need be magnetized along theirlongitudinal axis, which produces a stronger magnetic field. A method ofbulk magnetizing the articles in such a manner is described below.

FIG. 6 shows an apparatus for magnetizing such articles in bulk. Aconveyor 45 carries the articles 46, which are to be magnetized,arranged in random position on the belt 45. A magnetizer 47 isconstructed so as to allow the article to pass through its center and itis wound in to produce a magnetizing force field parallel to thedirection of movement of the articles. Two other magnetizers 48 and 49are placed adjacent to the conveyor 45 and are wound to produce amagnetic force field perpendicular to the direction of movement of thearticles 46 on the conveyor 45.

To facilitate detection, it is desirable that the articles 46 bemagnetized along their longitudinal axis. When the article to bemagnetized passes the magnetizer units 47, 48 and 49, it will besubstantially parallel to either the magnetic force field produced bymagnetizer unit 47 or the field produced by the magnetizer units 48 and49. It has been found there is little magnetic strength in any fieldproduced across the width of the magnetized articles 46. Thus, anarticle which is magnetized by passing through a parallel force field isnot neutralized by passing through a second magnetic force fieldperpendicular to it since only the width is exposed to this secondfield. If the articles 46 are to be magnetized in the form of the goodsor commodities to be protected, they will be normally packaged in such away so as to be perpendicular to the magnetizer unit 47 or perpendicularto the units 48 and 49. If the article is not packaged but is lyingloosely on the conveyor, the magnetic field produced by the magnetizerunits will have a tendency to align the articles 46 passing by. In bothcases the articles 46 are magnetized along their longitudinal axes.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

I claim:

1. In a system for the prevention of pilfering of articles passingthrough a pathway wherein there are plural distinct routes, said systemhaving a means for demagnetizing said articles passing only through oneroute and sensing means situated at the exit of said pathway for sensingthe magnetic field of all articles passing through all routes, thecombination with a plurality of detectable magnetic fields carried byeach article wherein at least two of the magnetic fields are disposed ina different direction such that both cannot be neutralized at the sametime by a single external source.

2. The system of claim 1 wherein said articles have a strip component ofmagnetized material, said component having two detectable magneticfields of opposite polarity wherein poles of similar polarity of saidmag netic fields are positioned immediately adjacent each other and theother poles of similar polarity are placed in the opposite ends of saidstrip component.

3. The system of claim 2 wherein said component strip has two detectablemagnetic fields thereon arranged in a parallel, side-by-siderelationship, the polarity of one of said magnetic fields being oppositein direction to the polarity of said second magnetic field.

4. The system of claim 1 wherein said articles have a circular componentof magnetized material, said circular component having similar poles ofone polarity located at the center of said circular component, andsimilar poles of the opposite polarity located at the radial extremitiesof said circular component.

5. In a system for the prevention of pilfering of articles from asecurity area, said security area having an entrance and exit pathway,said system having a sensing means situated at the exit of said pathwayfor sensing the magnetic field of all articles passing through the exit,the combination with a plurality of detectable magnetic fields carriedby each article wherein at least two of the magnetic fields are disposedin a different direction.

6. in the process for preventing the pilfering of articles passingthrough a pathway, said pathway having plural distinct routes,comprising supplying said articles with a detectable magnetic field,placing a demagnetizing field in only one route, demagnetizing only thearticles passing through said field, positioning a magnetic sensingdevice at the exit of said pathway and sensing the magnetic field of allsaid articles passing through any one of said routes for detecting anyarticles which have not been demagnetized, the combination with the stepof actively supplying each of said articles with a plurality of magneticfields wherein at least two magnetic fields are disposed in a differentdirection.

7. In the process of claim 6 including the step of actively supplyingeach article with a strip component having two detectable magneticfields of opposite polarity wherein poles of similar polarity of saidmagnetic fields are positioned immediately adjacent each other and theother poles of similar polarity are placed in the opposite ends of saidstrip component.

8. In the process of claim 6 including the step of supplying eacharticle with a strip component having two detectable magnetic fieldsthereon arranged in a panellel, side-byside relationship, the polarityof one of said magnetic fields being opposite in direction to thepolarity of said second magnetic field.

9. In the process of claim 6 including the step of actively supplyingeach article with a circular component of magnetized material, saidcircular component having similar poles of one polarity located at thecenter of said circular component, and similar poles of the oppositepolarity located at the radial extremities of said circular component.

10. In a process for preventing the pilfering of articles comprisingproviding a security area in which goods are to remain, said securityarea having an entrance and exit pathway, actively supplying saidarticles located in the security area with a detectable magnetic field,positioning a magnetic sensing means at said exit pathway, sensing themagnetic field of said articles which pass into said exit pathway andpreventing the removal of said articles from the security area, thecombination with the step of actively supplying each of said articleswith a plurality of magnetic fields wherein at least two magnetic fieldsare disposed in a different direction.

1. In a system for the prevention of pilfering of articles passingthrough a pathway wherein there are plural distinct routes, said systemhaving a means for demagnetizing said articles passing only through oneroute and sensing means situated at the exit of said pathway for sensingthe magnetic field of all articles passing through all routes, thecombination with a plurality of detectable magnetic fields carried byeach article wherein at least two of the magnetic fields are disposed ina different direction such that both cannot be neutralized at the sametime by a single external source.
 2. The system of claim 1 wherein saidarticles have a strip component of magnetized material, said componenthaving two detectable magnetic fields of opposite polarity wherein polesof similar polarity of said magnetic fields are positioned immediatelyadjacent each other and the other poles of similar polarity are placedin the opposite ends of said strip component.
 3. The system of claim 2wherein said component strip has two detectable magnetic fields thereonarranged in a parallel, side-by-side relationship, the polarity of oneof said magnetic fields being opposite in direction to the polarity ofsaid second magnetic field.
 4. The system of claim 1 wherein saidarticles have a circular component of magnetized material, said circularcomponent having similar poles of one polarity located at the center ofsaid circular component, and similar poles of the opposite polaritylocated at the radial extremities of said circular component.
 5. In asystem for the prevention of pilfering of articles from a security area,said security area having an entrance and exit pathway, said systemhaving a sensing means situated at the exit of said pathway for sensingthe magnetic field of all articles passing through the exit, thecombination with a plurality of detectable magnetic fields carried byeach article wherein at least two of the magnetic fields are disposed ina different direction.
 6. In the process for preventing the pilfering ofarticles passing through a pathway, said pathway having plural distinctroutes, comprising supplying said articles with a detectable magneticfield, placing a demagnetizing field in only one route, demagnetizingonly the articles passing through said field, positioning a magneticsensing device at the exit of said pathway and sensing the magneticfield of all said articles passing through any one of said routes fordetecting any articles which have not been demagnetized, the combinationwith the step of actively supplying each of said articles with aplurality of magnetic fields wherein at least two magnetic fields aredisposed in a different direction.
 7. In the process of claim 6including the step of actively supplying each article with a stripcomponent having two detectable magnetic fields of opposite polaritywherein poles of similar polarity of said magnetic fields are positionedimmediately adjacent each other and the other poles of similar polarityare placed in the opposite ends of said strip component.
 8. In theprocess of claim 6 including the step of supplying each article with astrip component having two detectable magnetic fields thereon arrangedin a parrellel, side-by-side relationship, the polarity of one of saidmagnetic fields being opposite in direction to the polarity of saidsecond magnetic field.
 9. In the process of claim 6 including the stepof actively supplying each article with a circular component ofmagnetized material, said circular component having similar poles of onepolarity located at the center of said circular component, and similarpoles of the opposite polarity located at the radial extremities of saidcircular component.
 10. In a process for preventing the pilfering ofarticles comprising providing a security area in which goods are toremain, said security area having an entrance and exit pathway, activelysupplying said articles located in the security area with a detectablemagnetic field, positioning a magnetic sensing means at said exitpathway, sensing the magnetic field of said articles which pass intosaid exit pathway and preventing the removal of said articles from thesecurity area, the combination with the step of actively supplying eachof said articles with a plurality of magnetic fields wherein at leasttwo magnetic fields are disposed in a different direction.